A team of researchers studying the food-and-drink buying habits of walkers, cyclists and bus riders fully expected to find that non-car users made more trips to the grocery store, since it's hard to haul home six boxes of pasta, two chickens and a carton of eggs without using a trunk. But it turns out that eaters who don't travel by car also visit restaurants and bars more frequently -- and run up higher tabs than their car-bound counterparts.

Although it's not yet clear what accounts for the discrepancy -- existing evidence doesn't point solely to the explanation that money saved on gas gets spent on food and booze -- Portland State University's Kelly Clifton called the finding that pedestrians, cyclists and bus riders are "competitive consumers" a "pleasant surprise."

Customers classified by mode of transportation

"I think there is a tremendous marketing opportunity here," e-mails Clifton, who led the study for the Oregon Transportation Research and Education Consortium. "These are loyal customers, "regulars." On average, pedestrians tend to go to the grocery store 13 times per month, compared to about eight times for automobile users. So these customers are in a grocery store one more time per week. I see a lot of value in trying to better engage with this market segment."

According to the study, merchants tend to overestimate how many customers rely on cars for transportation, and therefore resist measures to support multimodal travel, such as reducing parking or installing bike lanes, for fear the developments will hurt their businesses. But many of the previous studies which have tested the validity of retailers' claims have focused on narrow geographic areas: To more generally establish the buying power of the car-free population, researchers surveyed customers at 89 businesses in metro Portland.

Clifton concedes Portland's bike culture is unique, but says, "While the rates of cycling may be greater here than elsewhere, the spending amounts and customer behavior may be similar to other cities. The findings for pedestrians and transit users are even more likely to have similarities with other places."

Estimated average spending per month

Researchers hope their study will inspire more scrutiny of the relationships between transportation choices and consumer behavior, and perhaps lead to restaurateurs and bar owners better accommodating customers who don't arrive via car. Clifton believes the study suggests business owners could benefit from offering more delivery services; discounting bills for customers with transit passes or bike helmets and constructing covered bike parking.

"Transit users and pedestrians often have to negotiate a sea of parking to enter an establishment," she adds."Creating separate entrances oriented more to the street or to the neighborhood is one way to accommodate these patrons. In the end, business that pay close attention to their modal access - being proximate to transit, near bicycle lines and dense neighborhoods - will attract customers using a variety of modes."